Preface

Changed this time jetson xavier nx Development board , Think about compiling and installing with source code ros-melodic, It also took a lot of time , But it didn't work （ It's the last step to compile, actually ）, It is a pity that , But there are also some experiences .

First, let's talk about system configuration

After I bought it, the merchant installed it ubuntu18.04 System , Use gcc-7,opencv4（ That's the point ）,python2.7, Ready to install ros

1. add to ros Source

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'

2. add to ros After the source, the system does not trust the source , So do the following two steps , Add public key .
   The second step is due to github Interview questions , I have added agents , Just copy and run directly .

sudo apt install curl

curl -s https://ghproxy.com/https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -

3. Update source . Do not use domestic sources , Just follow my steps , Then, if there is no error in updating the source in this step .

sudo apt update

4. install ros Management tools

sudo apt-get install python-rosdep python-rosinstall-generator python-vcstool python-rosinstall build-essential

5. The following operations require access github, So let's modify the corresponding file , Add proxy .
   Add “https://ghproxy.com/”, Such as ：
   https://ghproxy.com/https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
   The specific operation documents are as follows ：

/usr/lib/python2.7/dist-packages/rosdep2/gbpdistro_support.py 36 That's ok 
/usr/lib/python2.7/dist-packages/rosdep2/sources_list.py 72 That's ok 
/usr/lib/python2.7/dist-packages/rosdep2/rep3.py	39 That's ok 
/usr/lib/python2.7/dist-packages/rosdistro/manifest_provider/github.py 68 That's ok  119 That's ok 
/usr/lib/python2.7/dist-packages/rosdistro/__init__.py 68 That's ok 

The following documents also need to be modified ：

/usr/lib/python2.7/dist-packages/rosdep2/sources_list.py 312 That's ok 
 add to  url="https://ghproxy.com/"+url
/usr/lib/python2.7/dist-packages/rosdep2/gbpdistro_support.py 204 That's ok 
 add to  gbpdistro_url = "https://ghproxy.com/" + gbpdistro_url

thus , The proxy of all codes is set . Be careful , We don't have to change 20-default file .

6. perform ros initialization

sudo rosdep init
rosdep update

If it is your second execution rosdep init Word of the file , Then it will prompt that it already exists 20-default file , Then delete it and run it .

7. Create a workspace

mkdir ~/ros_catkin_ws && cd ~/ros_catkin_ws

8. Install the corresponding version according to your needs ROS

• Desktop-Full Install：

rosinstall_generator desktop_full --rosdistro melodic --deps --tar > melodic.rosinstall

• Desktop Install (recommended)

rosinstall_generator desktop --rosdistro melodic --deps --tar > melodic.rosinstall

• ROS-Comm: (Bare Bones)

rosinstall_generator ros_comm --rosdistro melodic --deps --tar > melodic.rosinstall

8. download ros Source code

vcs import src < melodic.rosinstall

If the prompt does not src, Then create one by yourself , Make sure there is no error in this step of downloading , If something goes wrong, repeat it several times , After changing the agent, there may also be package download errors due to instability .

9. modify melodic.rosinstall file .
   After the previous step, we will ros_catkin_ws Create a melodic.rosinstall file
   After the light , Follow the steps 5 equally , Add before all links https://ghproxy.com/. Here we use Ctrl + H Just replace it all . Save and exit .
10. Make sure you have all the necessary installation dependencies , Just execute the following .

rosdep install --from-paths src --ignore-src --rosdistro melodic -y

11. Start compilation

./src/catkin/bin/catkin_make_isolated --install -DCMAKE_BUILD_TYPE=Release

• This step is where I failed , According to my system , Only installed opencv4, however ros The dependencies inside are opencv3, So I installed opencv3. For details, please refer to the following articles .
  wsl（Ubuntu 18.04 LTS） install openCV3.4.16 and openCV_contirb3.4.16
  ubuntu18 Compile below opencv4.2.0 CUDA edition , Integrated into the Anconda in
  about opencv The problem of slow download speed ,gitcode There is a corresponding image , cracking . as follows ：

https://gitcode.net/opencv

• The last step is to solve part of the problem , If you report this problem incorrectly ：

c++: internal compiler error: Killed (program cc1plus)

Then the probability is that there is not enough memory to kill the process , Open up a temporary exchange zone in the following way ：
Open up exchange space

• ok, The above two steps may lead to my failure , First look at the error ：

Note that this error is different from the last one , Last yes killed, Here is Segmentation fault (program cc1plus), Then read other blogs and say yes gcc The reason why multithreading is not supported , I will use it.
make -j1 I tried. No , Then he said gcc Version of the problem , I downloaded many versions again , It hasn't been solved yet , Everyone who has experience can come to the comment area for guidance .

summary

ROS It's the hardest thing for me to install , The most troublesome system , Not one of them. ！